If you've been to a conference or meeting in the last decade, you are familiar with the routine. Speaker approaches podium, pulls out laptop, fires it up and orders the lights turned down. The inevitable technical glitch is resolved and soon you are watching a PowerPoint presentation.

Eventually, your eyes glaze over, innocent victims of a full-frontal assault by too many slides, too much information, too little personality and bizarre patterns of colours reminiscent of a bad LSD trip circa 1968. There is no sanctuary, other than a nap or repetitive glances at your watch. Three days later, just like that bad LSD trip, all traces of the speaker's message have been wiped from the memory bank.

Some unfortunate conference participant, undoubtedly still suffering flashbacks, who harbours a lingering animus towards Bill Gates and his software, once dubbed the PowerPoint presentation as "Killing You Microsoftly". Such an invidious metaphor is unfair. To death. At least when you die, you're fortunate enough to have endured your last PowerPoint presentation. The unlucky who go on living must continue to endure PowerPoint, an invasive species threatening the information ecosystem, the kudzu of software.

And like kudzu, PowerPoint continues to proliferate beyond the boardroom, medical meeting and conference room. It has become a preferred method of presentation for the US Military and Pentagon. The linear, concise format makes it easily adaptable for the standard military briefing, even at the expense of clarity and content. Reportedly, when a critical briefing is required, some senior officers unfamiliar with PowerPoint seek out subordinates who have technical mastery of the software's nuances, dubbed "PowerPoint Rangers". As Margaret Hayes of Washington's National Defence University once said: "You can't speak with the US military without knowing PowerPoint."

Not that it necessarily makes for a better fighting force. General David Petraeus describes sitting through a presentation as "just agony". During a discussion between US and Russian officers serving in Bosnia, a Russian officer familiar with American PowerPoint military culture, opined – only half in jest – that the Russians would have won had the two sides had ever actually fought in western Europe. How? "While you were making your slides, we would be killing you."

Not everyone is a dedicated follower of fashion. Australian researchers have discovered information is best processed either orally or in writing, but not both ways simultaneously. Thus, PowerPoint presentations can backfire when what's on the screen is the same as what the speaker is saying, because audience attention is automatically divided. One British journalist compared trying to follow what someone is saying while watching the same words on a screen, to the act of riding a bicycle down the aisle of a moving train – you feel like you're making extra progress, but you're not really going anywhere. Professor John Sweller of the University of New South Wales, Australia concluded simply: "The use of the PowerPoint presentation has been a disaster. It should be ditched". He did not find it necessary to use colour slides to make this point.

Renowned Canadian communications theorist Marshall McLuhan anticipated much of this when he described the influence television, computers and other electronic dissemination of information would eventually have on society and mass culture. (Nearly half a century ago, McLuhan predicted the obsolescence of the printed book. Amazon's digital sales recently overtook print sales.) McLuhan's most famous aphorism, "The medium is the message", anticipated that people would be influenced increasingly by how a message was delivered rather than by its content.

This is in line with the current PowerPoint culture. PowerPoint can leave an audience persuaded, but not necessarily better-informed. Two of the most consequential speeches of the 21st century – Colin Powell's warning to the United Nations about Saddam Hussein's Iraqi weapons of mass destruction, and Al Gore's jeremiad on global warming – were not actually speeches, as traditionally understood, but PowerPoint presentations. In retrospect, both emphasised rhetoric at the expense of facts.

Ultimately, the danger of PowerPoint is not the inefficient or imprecise transfer of information but that, more than ever, style is replacing substance. Hard information, once transmitted through speeches and reports that demanded interpersonal interaction, can now be drowned out by slick graphics and oversimplified images. The ill-informed novice, with a polished presentation can trump the presenter with valuable information who lacks technical sophistication. For all its utility, PowerPoint threatens to become merely one more tool that is dumbing down society in an era of declining newspaper readership and broadcast news as little more than entertainment.

"We shall defend our island whatever the cost may be. We shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills …"